DOI: 10.36347/sjavs.2017.v04i01.003

Pages: 13-17

Drought is an alarming issue limiting crop production worldwide and is becoming increasingly severe with the passage of time in Bangladesh. Rice production in Bangladesh is thus, being adversely hampered by drought. Therefore a pot experiment was carried out with six rice genotypes to assess the effect of drought stress on grain dry weight, photosynthesis and chlorophyll content during July to December 2013-2014 at Bangladesh Institute of Nuclear Agriculture, Mymensingh, Bangladesh. Drought stress (control and 40% FC) was imposed on Binadhan-13, Kalizira, BRRI dhan-34, Ukunimodhu, RM-100-16 and NERICA mutant rice genotypes at grain filling stage (anthesis to maturity) and discontinued when the specific stage was over. The experiment was laid out in a Complete Randomized Design with three replications. Grain dry weights of 10 grains of selected panicles, chlorophyll content (SPAD reading) and photosynthetic rate of flag leaf were measured at 3 days interval from anthesis to maturity. Data was recorded at anthesis to maturity. Drought stress decreased grain dry weight, photosynthetic rate and chlorophyll content of flag leaf significantly. The highest grain dry weight, chlorophyll content and photosynthetic rate were found in Binadhan-13 and NERICA mutant. Grain dry weight increased with age till 24 days after anthesis followed by a Plateau whereas SPAD reading and photosynthesis rate decreased with grain age until physiological maturity. From the current research, it appeared that increased drought tolerant mechanisms were observed in the genotypes NERICA mutant and BINAdhan-13.